用于谐波劣化分析的并网逆变器阻抗灰箱拟合方法  

A Gray-Box Fitting Method of Grid-Connected Inverters Impedance for the Analysis of Harmonic Degradation

作　　者：吴滨源 李建文 李永刚 王月 孙伟 Wu Binyuan;Li Jianwen;Li Yonggang;Wang Yue;Sun Wei(State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University,Baoding 071000 China;Baoding Power Supply Subsidiary Company of State Grid Hebei Electric Power Supply Co.Ltd,Baoding 071000 China)

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学),保定071000 [2]国网河北省电力有限公司保定供电分公司,保定071000

出　　处：《电工技术学报》2022年第4期942-953,共12页Transactions of China Electrotechnical Society

基　　金：河北省自然科学基金(E2017502053);中央高校基本科研业务费专项资金(2020MS095)资助项目。

摘　　要：大规模分布式新能源经逆变器接入配电网,并网逆变器与弱电网间形成复杂交互,谐波劣化问题凸显。谐波劣化分析的关键之一是并网逆变器阻抗模型的建立。白箱阻抗建模需要结构、参数、控制方式等内部信息,黑箱阻抗建模结果一般无物理意义,两种建模方法均存在应用缺陷。为弥补二者的不足,该文以白箱阻抗建模的结果为求解目标,以黑箱阻抗建模的方法为求解途径,通过有理函数逼近算法灰箱拟合并网逆变器阻抗传递函数。首先通过双模式扰动获取离散阻抗数据;然后利用矩阵束改进矢量匹配法,实现初始参数的自动获取,缩短迭代计算耗时;再次基于RT-Lab搭建半实物实时仿真平台,通过对比实验验证该文方法的有效性和优势;最后基于阻抗拟合结果开展谐波劣化分析,验证该文方法的实用性。As a large number of distributed generation systems are connected to the grid through inverters,complex interactions between grid-connected inverters and weak-grids are formed,and the problem of harmonic degradation is prominent.One of the key points of harmonic degradation analysis is to establish the impedance model of the grid-connected inverter.The detailed internal information is needed in white-box impedance modeling,and the results of black-box impedance modeling are meaningless.Both methods have defects in practical engineering application.Therefore,setting the result of white-box as the goal and taking the method of black-box as the solution way,this paper presents that the impedance of the grid-connected inverters in gray-box is fitted by rational function approximation.First of all,the discrete impedance data are obtained by dual-mode disturbance,and then the matrix pencil method is used to extract the initial parameters and reduce the time of iterative calculation.An improved vector fitting is proposed.Then a hardware in the loop real-time simulation platform is built based on RT-Lab,and the effectiveness and advantages of this method are verified by comparative experiments.Finally,the analysis of harmonic degradation is carried out based on the results of impedance fitting to verify the practicability of the proposed method.

关 键 词：并网逆变器 谐波劣化 阻抗分析法 有理函数逼近 RT-LAB 

分 类 号：TM712[电气工程—电力系统及自动化]